Use 4 non-magnetic screws of a size to fit boat. Screw through bracket base and into boat. Use sealant to seal bracket to boat.

If bracket is in a position likely to be snagged by ropes: Use the two eyelets at top of bracket to fasten elastic around mast.
Bracket is then a permanent fixture. Simply attach Tacktick instrument to the bracket by means of the 4 thumb nuts each time you sail.

Note:
Compass is accurate only when mounted within 20º of the vertical. Do not lean compass to port or starboard. Do not use within 2' or 0.6 m of magnetic objects unless your instrument can be calibrated. Note that a conventional compass is a magnetic object. Ensure mounting bracket is secure and check that security bolts are tight before each race.